I love the Jane Goodall documentary about the Chimpanzees of Gombe. I was particularly fascinated by the way victorious alpha males would comfort the beta males they'd just finished dominating into submission--hugging them, grooming them, cupping their genitals. Of course, humans are a lot like that, although I personally could do without having my boss cup my genitals. But after some conflict within my tribe du jour--be it church or work or social group or family get togethers--it's always helpful if there's some behavior, spontaneous or ritualized, to help smooth over feelings.
The central bonding ritual among the chimps was grooming. Out in the jungle a full EdAsner of back hair is highly susceptible to acquiring gnats and other microvermin. One way the chimps display their love and acceptance of one another is to spend hours picking the bugs off one anothers' backs and eating them (yay protein!), alphas generally going first. When someone eats the bugs right off your back, you know you're loved and protected; you can feel it in very concrete terms.
Now being in a group constantly inclines animals, particularly smart, territorial, opinionated animals like primates. The grooming is absolutely vital to maintaining community cohesion.
Jump forward a few gazillion years. Anthropologists theorize that the development of language among earlier models of mankind came about as a substitute for picking gnats. For environmental reasons, humans assumed increasingly upright postures. Either they had to see each other over tall grasses or needed to spread out more to surround their prey or whatever. The point is, they spent less time in arm's reach of one another. Their interactions became smarter and thus more complex and thus more inclined to misunderstanding and conflict.
Thus the acquisition of language, according to this theory, became necessary as a direct substitute for eating the fleas off each others' backs. Spoken communication can bond us without being so yucky. This is why spoken language is so dependent on ritual: the point often isn't communication of ideas so much as the communication of another tribe member's mere presence.
Those nonverbal rituals still do the job better, I think. Verbal interactions too easily degenerate from gnat-picking to nit-picking. Maybe this is why the internat, I mean internet, is so full of miscommunication. Sure I called you a nazi, but what I really meant to say is I love you.